Mosey, mine still works! Only 2 deer incidents this year, 1 night forgot to turn it on (see below), the other when we went out of town for several days and left them on - batteries went dead, but they were old anyway.
As mentioned, I do have 2, across from each other, slightly angled apart. Very effective.
I got one from scatmat (actaully a "gift" from my son), then the other locally. You can buy them all day on ebay for $50 as I recall.
I would like to see a feature or 2 added - an adjustable photocell so you don't have to turn it off and on, and maybe a solar plate to enhance battery life, although even left on, they last a pretty good while, as long as you don't wait until they are almost spent and go out of town!
Good Luck!
Dob